Recently, a heterogeneous network has been suggested as the next-generation communication network. This heterogeneous network is a network in which a plurality of kinds of small-or-medium-scale base stations coexist in a macro-cell by performing overlay transmission or spectrum sharing. A Remote RadioHead (RRH) cell base station, a hot zone base station (Pico/micro-cell eNB), a femto-cell base station (Home eNB), a relay device (relay base station), and the like are referred to as small-or-medium-scale base stations.
Each small-or-medium-scale base station described above, for example, can perform an operation for reinforcing link quality between a communication terminal and a macro-cell base station, an operation for increasing an area capacity, an operation for extending communication coverage, or an operation for operating an independent cell.
There are many technologies for controlling an operation of the above-described small-or-medium-scale base station from a fixed network side. For example, the fixed network side can reduce power consumption of the small-or-medium-scale base station by managing a sleep mode of the small-or-medium-scale base station. As an example of the small-or-medium-scale base station, a relay apparatus is disclosed, for example, in Non-Patent Literature 1.